Connectome-based biophysical modeling of a figure-ground discrimination circuit
- 1Massachusetts Institute of Technology
Abstract
Figure-ground discrimination via relative motion represents a highly conserved visual computation essential for uncovering camouflage \citep{reichardt1983figure,Egelhaaf1985}. Over forty years ago, the Reichardt-Poggio-Hausen (RPH) model proposed a circuit architecture to explain this phenomenon, relying on an inhibitory wide-field pool cell to aggregate global motion and subsequently inhibit elementary motion detectors. Here we combine a whole-brain connectome of Drosophila with biophysical simulations to identify a reciprocal connection between T4a motion detectors and the wide-field ventral Centrifugal Horizontal cell. The anatomical feedback from vCH lands on T4a axon terminals; simulated dendrites generate local direction-selective responses, whereas the terminals become selective for relative motion. The isolated reciprocal circuit is sufficient for this selectivity which is abolished by removing the return inhibition. Opponent-motion and interocular pathways strengthen the same computation. Thus, a single neuron using the biophysical mechanism of shunting inhibition, corresponding to an equilibrium potential close to the resting potential, can support distinct visual operations in separate compartments: local motion in its dendrites and relative motion in its axon.
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BibTeX
@misc{ziyin2026connectomebased,
title = {{Connectome-based biophysical modeling of a figure-ground discrimination circuit}},
author = {L. Ziyin and Y. Lu and A. Borst and S. Dorkenwald and T. Poggio},
howpublished = {bioRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.17.752514},
url = {https://www.biorxiv.org/content/10.64898/2026.09.17.752514v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Connectome-based biophysical modeling of a figure-ground discrimination circuit
AU - L. Ziyin
AU - Y. Lu
AU - A. Borst
AU - S. Dorkenwald
AU - T. Poggio
PY - 2026
DA - 2026/09/17
PB - bioRxiv
DO - 10.64898/2026.09.17.752514
UR - https://www.biorxiv.org/content/10.64898/2026.09.17.752514v1
AB - Figure-ground discrimination via relative motion represents a highly conserved visual computation essential for uncovering camouflage \citep{reichardt1983figure,Egelhaaf1985}. Over forty years ago, the Reichardt-Poggio-Hausen (RPH) model proposed a circuit architecture to explain this phenomenon, relying on an inhibitory wide-field pool cell to aggregate global motion and subsequently inhibit elementary motion detectors. Here we combine a whole-brain connectome of Drosophila with biophysical simulations to identify a reciprocal connection between T4a motion detectors and the wide-field ventral Centrifugal Horizontal cell. The anatomical feedback from vCH lands on T4a axon terminals; simulated dendrites generate local direction-selective responses, whereas the terminals become selective for relative motion. The isolated reciprocal circuit is sufficient for this selectivity which is abolished by removing the return inhibition. Opponent-motion and interocular pathways strengthen the same computation. Thus, a single neuron using the biophysical mechanism of shunting inhibition, corresponding to an equilibrium potential close to the resting potential, can support distinct visual operations in separate compartments: local motion in its dendrites and relative motion in its axon.
ER -